When using the Poisson as an approximation to the binomial, which of the following conditions apply for the best approximation?

OPTIONS

• Larger sample size and larger fraction defective
• Larger sample size and smaller fraction defective
• Smaller sample size and larger fraction defective
• Smaller sample size and smaller fraction defective

ANSWER

Larger sample size and smaller fraction defective

EXPLANATION

This question requires an understanding of the Poisson and binomial distribution formulas and a review of the answers. The Poisson is an approximation to the binomial distribution when the probability of occurrence is equal to or less than 0.1 and the sample size is large. The smaller the fraction defective and the larger the sample size, the better the approximation.